They came to the nation's capital to hear a great African-American orator offer his vision for the future from the steps of the Lincoln Memorial, the gleaming marble monument that honours the President who ended slavery.
But yesterday, exactly half a century after Martin Luther King's "I Have a Dream" speech, it was Barack Obama they had gathered to hear.
On a sweltering August afternoon in 1963, Dr King, the Baptist preacher and civil rights leader, had drawn the largest crowd the country had witnessed as he delivered the rousing call for racial equality that reverberates to this day.
Yesterday, under rainy skies, America's first black President stood on the same spot to remind the country of the remarkable progress that has been made in the five decades since the March on Washington.
"We rightly and justly remember Dr King's soaring oratory that day," Obama declared. "His words belong to the ages. But we also remember that that day also belonged to those ordinary people whose names never got in the history books.
There were couples in love who couldn't marry, soldiers who fought for freedoms abroad that were denied to them at home."
As a result, he said, "America changed ... And yes, eventually the White House changed."
Earlier, he had told African-American religious leaders: "I stand on the shoulders of Dr King."
But he also noted how far America still had to go to fulfil Dr King's dream.
"When it comes to the economy, when it comes to inequality, when it comes to wealth, he would say that we have not made as much progress as the civil and social progress that we've made, and that it's not enough just to have a black President."
About a quarter of the 1963 crowd was white and Dean Beery, a young man from Chicago, was one of them. He returned yesterday with his wife Reba.
"I was working in inner-city Chicago and I could see racism up close at first hand," he said. "I wanted to be here today to remember that day and honour Dr King's legacy but also because there is still so much discrimination and inequality in our society."